Placer-mining dredge.



N0. 747,086;v PATENTED DEC. 15, 1903. A. W. ROBINSON.

PLACER MINING DRBDGB. APPLIOATION FILED MA! 20, 1902.

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W I i q I wilmeooeo fx and 6 No. 747,086. PATENTED DEC. 15, 1903. A. W. ROBINSON.

PLACER MINING DREDGE.

APPLICATION FILED MAY 20, 1902.

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PATENT Trice.

.PLACERHVHNING HEDGE.

SPECIFICATION formingpart of Letters Patent No. 747,086, dated December 15, 1903.

Application filed May 20, 1902. Serial No. 108,271. (No model.)

Io all whom it may concern:

Be it known that I, ARTHUR W. ROBINSON, a citizen of the Dominion of Canada, and a resident of the city of Montreal, in the Province of Quebec, Dominion of Canada, have invented a certain new and useful Improvement in Placer-Mining Dredges and the Like Structures, of which the following is a full, clear, and exact specification, reference being had to the accompanying drawings.

My invention relates to that class of dredges in which an endless chain of buckets is employed to dredge the material and deliver it into a rotary screen; and the object of my invention is to provide a convenient and simple means of transmitting power to the upper tumbler-shaft of such a dredge, in conjunction with which I employ a special method of driving the rotary screen used in connection therewith.

The invention also includes the method of constructing the parts and combining them together in such a manner that they are easilyl erected and taken apart and supported in a strong and simple manner.

In the drawings hereof, Figure 1 represents a side elevation of a dredge embodying the invention. Fig. 2 is a side elevation, somewhat enlarged, of the parts more immediately involved in the invention. elevation of the moreimportant parts shown inFig. 2, partly in section.

A is the scow or float of the dredge. Any equivalent support for the mechanism may be substituted therefor.

B is the rotary screen, which may be of any usual or convenient form. Itis supported at an inclination and receives all the material at the upper end, discharging the coarser material at the lower end, while the perforations in it permit the fine material to pass through into the sluice-box O. Streams of water are introduced both into the screen and into the sluice-box to aid in washing the material.

All the above is in construction and operation such as is now in common use.

D is the upper tumbler, upon which the buckets E travel, they being connected to the usual bucket-chain F, and as they come over the top of the tumbler they empty their contents into a hopper G, (see Fig. 2,) which con- Fig. 3 is an end nects with the screen in a manner well understood.

H is the main driving-gear of the tumblershaft I, and J is the pinion. It is mounted on an intermediate shaft K, on one end of which outside the framing is a belt-pulley L, which is driven by a belt from an engine on deck.

M is a small beveled gear on the intermediate shaft K, which drives a corresponding beveled gear N, mounted on a short shaft 0 at right angles to the intermediate shaft K. This beveled gear has attached to it a spurpinion P, which drives the screen,and a spurgear Q,encircling the upper end of the screen.

The two shafts-to wit, the main shaft I and the intermediate shaft K--are mounted on two inclined frames R R. They are placed in this position for the purpose of carrying the two shafts in their proper relation to each other, and also for the purpose of bracing the framework generally. These side frames R R extend downwardly to the deck of the scow and are strongly framed or otherwise supported upon it, and thus they form a brace against fore-and-aft movement and against the thrusting strains of the bucket-ladder S. These side frames are carried upwardly sufficiently far to permit a cross-piece T, (see Fig. 3,) connecting their upper ends beyond the space occupied by the buckets, to be used, whereby the strength and rigidity of the frames are greatly increased. The side frames are each supported by a pair of uprightsU U,which are shown in the drawings as made of timber and connected at their upper ends" by a suitable casting V. They may, however, be made of metal, such as angle-iron or steel, the same principle being employed.

The chain of buckets are carried upon a ladder-frame in the usual manner. The upper end of this ladder is supported upon the ladder suspension shaft W, the bearingpieces W for which are attached to the front inclined braces U near the point where they connect with the inclined frames R. The bearings for the main or tumbler shaft I are, as shown in Fig. 2, supported upon the upper surface of the inclined frames Ft, directly in line with the axis of the front inclined braces U.

The operation of the apparatus is clear. The materialis elevated by the buckets in the usual manner, and the rotary movement of the screen is coincident with the operation of the buckets, because they are both driven from the same shaft-to wit, the intermediate shaft K. It is further to be noted that by my improved construction the parts revolve in their proper relation to one another. For example, when the buckets are discharging their contents the shaft is revolving in the direction of the arrow (see Fig. 3) and the screen is revolving in the direction likewise indicated by the arrow. This causes the material in the screen to assume the position indicated at X, and the receiving sluice-box underneath the screen'is disposed to one side of the axis of the screen, so as to receive the screened material more efficiently. It will also be noted that, as heretofore stated, the side frames are so constructed and arranged that they in a most effective manner support the mechanism and tend to resist the excessive strains and thrusts to which such a frame in such a machine is subjected.

It will be obvious to those who are familiar with this art that modifications may be made in the details of construction of my invention without departing from the essentials thereof;

I therefore do not limit myself to such details as are shown and described. It will also be obvious that my invention in whole or in i part is applicable to machines of this general class used for other purposes than placermining and under somewhat different conditionsas, for instance, in screening sand from a sand-bank, in the stone-crushing art, and the like.

Having described my invention, I claim' 1. The combination in a machine of the class stated of a main frame embodying two side frames, each composed of an inclined member supported at its base upon the general support of the structure, two supporting members connecting with the inclined members near their upper ends, one approximately in line with the thrust from the excavator, and a cross brace or member connecting the two side frames beyond the chain of buckets, an endless chain of buckets and means to actuate the same, a rotary screen and means to rotate the screen, said actuating devices being supported upon said frame, a motor for the parts located within the base of the triangle defined by the inclined members and a belt connected with said means and motor for the purpose set forth.

2. The combination in a machine of'the class stated of a main frame embodying two side frames, each composed of an inclined member supported at its base upon the general support of the structure, two supporting members connecting with the inclined members near their upperends, one approximately in line with the thrust from the excavator, and a cross brace or member connecting the two side frames beyond and out of the way of the chain of buckets, an endless chain of buckets and means to actuate the same supported upon said frame, a rotary screen and means to rotate the screen likewise supported upon said frame, a tumbler-shaft for the chain of buckets located upon said inclined members and substantially on the axial line of said supporting members, a motor for the parts located within the base of the triangle defined by the said inclined members-and a belt connected with said actuating devices and the motor for the purpose set forth.

In testimony whereof I have signed my name to this specification, in the presence of two witnesses subscribing hereto, this 30th day of April, 1902.

ARTHUR W. ROBINSON.

Witnesses:

J. B. ROBINSON, E. M. CORBET. 

